I have a hose bib on the side of my house and it's leaking. I tried to take it out so I can get the same one from the local hardware store. But wow! It won't come off! Maybe I'm not using enough force but I'm really afraid of snapping something behind the wall.
Is it usually soldered on? Or screwed on? The house was built in 1977.
Can I just get replacement parts? Like a new valve body or O-ring?
From where is it leaking? Around the stem or out the spout? If the first, loosen the packing nut, wrap packing around stem, retighten nut. If the spout, you'll have to replace the washer.
Likely is soldered; I'd be real careful about twisting it any more unless you can verify that it is threaded.
Picture of valve would likely help.